Almost as soon as the news broke in mid-August that Brazilian Socialist Party presidential candidate Eduardo Campos had been killed in a plane crash, fevered speculation focused on the prospects of his running mate, the former environment minister and 2010 presidential candidate Marina Silva. Party leaders quickly named her Campos's successor.

Though widely admired, Campos was trailing in third place before his death. A month later, Silva has transformed what was one of Brazil's duller campaigns into an extraordinary scramble for power between incumbent President Dilma Rousseff and a poor rubber-tapper who taught herself to read at the age of 16.

The latest polls, released Wednesday night, show a statistical dead heat between the two in a prospective second round.

Silva cut her political teeth as an activist in the Amazon, where standing up to illegal loggers or powerful farmers can be dangerous.

Silva has presented herself as a "third way" candidate, playing on her humble background and green credentials to attract voters weary of the establishment, while wooing the center-right with a manifesto of fiscally conservative economic reforms.

"She stands for fiscal responsibility and not irresponsibility, as is happening now under Rousseff," David Fleischer, a University of Brasilia political scientist, told VICE News. Silva has called for an end to "creative accounting," and has pledged to cut taxes on investment, eliminate government waste, and boost foreign trade.

The Brazilian economy expanded under the administration Luiz Inácio Lula da Silva, Rousseff's predecessor, becoming the world's seventh largest. Some 30 million people were lifted out of poverty and into the middle class. But the economy has flagged under Rousseff's management. The cost of living has outpaced salaries, and the emergent middle class is demanding a higher standard of public services. Recent indicators show that Brazil has slipped into recession, eroding Rousseff's support among the poor and working class.

"This government was like a bad marriage," Neide Moura de Brito Nascimento, a 49-year-old a housekeeper from Brasília, told VICE News. "The first year was great. But since then nothing has improved, and a lot has gotten worse."

Fleischer believes Silva's momentum will persist until the vote on October 5, and that she will win.

Her message is connecting with voters. The markets have surged along with her poll numbers, while younger voters, hundreds of thousands of whom took to the streets last year to protest corruption and poor public services, appreciate her distance from a political elite mired in scandal. Silva has also pledged to remain in office for only one term.

"She's speaking our language, she's saying things the youth want to hear," Andre Dutra, former president of the Socialist Party's youth division, told VICE News. "She's talking about a new way to do politics."

An alleged corruption scheme involving the state-owned oil firm Petrobras has become a particular concern for Rousseff. Recent leaked testimony from a jailed former Petrobras director claims that more than 40 politicians, including members of Rousseff's party as well as at least one minister in her government, received cash kickbacks from Petrobras dealings over the past 10 years in return for congressional votes.

Rousseff has not been directly implicated, and has insisted that she knew nothing of the allegations. Nevertheless, after serving as Minister of Mines and Energy under Lula and as his long-time chief of staff, during which she chaired the Petrobras board of directors, Rousseff has been embarrassed for failing to detect a scheme unfolding under her nose.

Silva quickly moved to score points after the testimony was leaked, declaring that Rousseff bore "political responsibility" for the scandal.

'Her history shows that she's a fighter.'If she wins the presidency, Silva will have completed an extraordinary journey from her impoverished roots.

She was one of eleven children born to parents in an isolated part of the Amazon jungle in Acre state who made a living walking miles daily through the forest, tapping rubber trees for their sap. Silva survived bouts of hepatitis, malaria, and the parasitic disease leishmaniasis, among other afflictions. Three of her siblings died in childhood.

At 16, she traveled to the state capital, Rio Branco, in search of education and medical treatment. She taught herself to read and gained university admission, working as a maid to cover her expenses.

Silva cut her political teeth as an activist in the Amazon, where standing up to illegal loggers or powerful farmers can be dangerous. She helped found Acre's first labor union and was an early member of Lula's Workers' Party. She promoted conservation alongside Chico Mendes, a famous environmentalist who was murdered in 1988 for his work protecting the rainforest. Later, as minister for the environment, Silva presided over a nearly 60 percent drop in the rate of deforestation.

After five years in Lula's cabinet, she resigned in frustration over the government's evident promotion of development over environmental protection, and soon left the Workers' Party. Silva ran as the Green Party's presidential candidate in 2010, finishing a distant third.

Her distinctive backstory is appealing to many voters who are tired of 20 years of two-party rule between the Workers' Party and the Brazilian Social Democracy Party, whose candidate Aecio Neves has about 15 percent support in first-round polling, compared to figures in the mid-thirties for Rousseff and Silva.

"She has strong convictions, sure beliefs," Nascimento said. "She's not just putting a sugar cube in people's mouths to make people think she's a good person for the duration of the election. Her history shows that she's a fighter."

But while some are encouraged by Silva's uniquely market-friendly socialist message, others are skeptical. She joined the Brazilian Socialist Party only last year, after failing to establish a sustainability-oriented political party of her own.

"I think that even her closest defenders who really believe in her don't really know what she stands for," Ivan Chiarelli, a composer from Sao Paulo, told VICE News. He said that Silva's attempts to win over farmers as a candidate had compromised her most clear-cut interests — sustainable development and protection for the Amazon.

Chiarelli is especially concerned about Silva's association with Brazil's strong evangelical lobby. She has been characterized as a fervent Pentecostal Christian, which puts her at odds with some of her party's progressive positions.

"It's not her faith, per se, it's the strings attached to the institutionalized religion," he said. "In recent weeks she's been clearly influenced by them."

Late last month, Silva hastily amended the support for gay marriage in her campaign manifesto to a support for gay civil unions, which many attributed to an attack on the position from an evangelical pastor on Twitter. Civil unions in Brazil give fewer rights to couples than marriage, such as the ability to inherit an estate.

Dutra, the former youth leader, said that while he believes young Brazilians generally support Silva, he is wary of some of her positions on issues of particular importance to that group.

"It's tricky, because she's totally against the regulation or legalization of marijuana, and totally against legalizing abortion, which is something that really affects younger people, because of her religious views," he said. "Taking out these issues, she's well-regarded."

Challenges certainly remain for Silva. Because of the size of Rousseff's political coalition, she enjoys five times as much televised advertising time as Silva — a crucial resource in a country where television is the main source of information for many outside of the biggest cities. And even if Silva manages to win, some wonder whether she will have the political capital needed to form a coalition in Brazil's congress, which has more than 20 political parties.

"Political support could be a big problem. She says she will govern with just the best people of any party, but it doesn't solve the problem of governance," Sonia Fleury, a political scientist professor at Rio's FGV Institute, told VICE News. "It's wishful thinking. You need to form alliances with parties as they are — good and bad together."

Fleischer, however, expects the Social Democracy Party to support Silva if she wins, and he noted that the Brazilian Democratic Movement Party, which holds a large number of congressional seats, has also hinted that it would work with her.

"With those two large parties, she has a good coalition already," he said.

But for many working-class Brazilians, what Silva symbolizes supersedes concerns about her religion or the size of her ruling coalition. The political ascendance of a poor, black woman suggests that anyone can become president.